Bacitracin Zinc: Increased risk of nephrotoxicity when used with other nephrotoxic drugs. May enhance the action of neuromuscular-blocking agents.
Polymixin B: Potentially Fatal: Additive neurotoxic or nephrotoxic effect w/ bacitracin, streptomycin, neomycin, kanamycin, gentamicin, tobramycin, amikacin, cephaloridine, paromomycin, viomycin, colistin. Increased risk of resp paralysis w/ neuromuscular blockers (e.g. anaesthetics, muscle relaxants).